bpo-38090: Fix reference leak in ceval.c (GH-15848)

diff --git a/Python/ceval.c b/Python/ceval.c
index d280d79..01e2a1b 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -5235,7 +5235,6 @@
     else {
         _Py_IDENTIFIER(__spec__);
         PyObject *spec = _PyObject_GetAttrId(v, &PyId___spec__);
-        Py_XINCREF(spec);
         const char *fmt =
             _PyModuleSpec_IsInitializing(spec) ?
             "cannot import name %R from partially initialized module %R "